Theoretical and Experimental Understanding of Hydrogen Evolution Reaction Kinetics in Alkaline Electrolytes with Pt-Based Core-Shell Nanocrystals

Jeonghyeon Kim, Haesol Kim, Won Jae Lee, Bibi Ruqia, Hionsuck Baik, Hyung Suk Oh, Seung Min Paek, Hyung Kyu Lim, Chang Hyuck Choi, Sang Il Choi

Research output: Contribution to journalArticlepeer-review

98 Scopus citations

Abstract

The free energy of H adsorption (ΔGH) on a metallic catalyst has been taken as a descriptor to predict the hydrogen evolution reaction (HER) kinetics but has not been well applied in alkaline media. To assess this, we prepare Pd@Pt and PdH@Pt core-shell octahedra enclosed by Pt(111) facets as model catalysts for controlling the ΔGH affected by the ligand, the strain, and their ensemble effects. The Pt shell thickness is adjusted from 1 to 5 atomic layers by varying the amount of Pt precursor added during synthesis. In an alkaline electrolyte, the HER activity of core-shell models is improved either by the construction of core-shell structures or by the increased number of Pt shells. These experimental results are in good agreement with the ΔGH values calculated by the first-principles density functional theory with a complex surface strained core-shell slab model. However, enhanced HER activities of Pd@Pt and PdH@Pt core-shell nanocrystals over the Pt catalyst are inconsistent with the thermodynamic ΔGH scaling relationship only but can be explained by the work function and apparent ΔGH models that predict the interfacial electric field for the HER.

Original languageEnglish
Pages (from-to)18256-18263
Number of pages8
JournalJournal of the American Chemical Society
Volume141
Issue number45
DOIs
StatePublished - 13 Nov 2019

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